A double-curved tube for McGrath® MAC videolaryngoscope-guided tracheal intubation

Usefulness of an automatic cuff pressure controller (SmartCuff) in inhibiting gasleakage around the cuff after tracheal intubation: a randomized controlled study

PURPOSE

Gas leakage around the cuff of a tracheal tube may frequently occur after tracheal intubation and inflation of the cuff. We assessed if the SmartCuff (Smiths Medical Japan, Tokyo, Japan), an automatic cuff pressure controller, would effectively prevent gas leakage.

METHODS

Seventy adult patients were allocated randomly to one of two groups. After induction of general anesthesia and tracheal intubation, in one group (Syringe group), a syringe was used to inflate the cuff, until there was no audible gas leakage, at the airway pressure at 20 cmH2O. In the other group (SmartCuff group), the SmartCuff was used to maintain the cuff pressure to be 20 cmH2O. The mechanical ventilation (tidal volume of 8 ml.kg-1 and 12 breaths per min) was started. The incidence and percentage of gas leakage, and the proportion of adequate seal (defined as gas leakage of < 10%) between the groups were compared.

RESULTS

The incidence of audible gas leakage was significantly higher in the Syringe group (10 of 35 patients (28%)) than in the SmartCuff group (none of 35 patients (0%)) (P = 0.00046, 95%CI for difference: 15-43%), and the proportion of adequate seal was significantly lower in the Syringe group (19 of 35 patients (54%)) than in the Smart cuff group (33 of 35 patients (94%)) (P = 0.0001, 95% CI for difference: 20-58%).

CONCLUSION

Gas leakage may frequently occur after tracheal intubation, and the use of the SmartCuff can effectively maintain the sealing effect of the cuff.

Efficacy of McGRATH®MAC videolaryngoscope blade 1 for tracheal intubation in small children: a randomized controlled clinical study

BACKGROUND

Videolaryngoscopes may not be as effective in small children as they are in older children and in adults. The size 1 blade is commercially available for the McGRATH®MAC videolaryngoscope (Covidien, Medtronic, Tokyo, Japan), but its efficacy in comparison with a Macintosh laryngoscope blade 1 is not known.

AIM

The main aim of this study was to assess the efficacy of McGrath®MAC blade 1 in comparison with a conventional Macintosh laryngoscope blade 1, in children aged less than 24 months.

METHODS

Thirty-eight children aged less than 24 months were randomly allocated to one of two groups, and tracheal intubation was attempted using either a direct laryngoscope with a Macintosh blade 1 or a videolaryngoscope with a McGRATH®MAC blade 1. In another 12 children aged 2-4 years, the same comparisons were made with blade 2. The primary outcome measure was time to tracheal intubation using a size 1 blade.

RESULTS

Tracheal intubation took significantly longer with a McGRATH®MAC blade 1 (median (interquartile range): 38.0 (31.8-43.5) s) than with the Macintosh blade 1(27.4 (25.9-29.2) s) (p < 0.0001; median difference (95% CI for the median difference): 10.6 (6.4-14.0) s), mainly due to difficulty in advancing a tube into the trachea. No significant difference was observed for the size 2.

CONCLUSIONS

In small children without predicted difficult airways, time to intubate the trachea was significantly longer for a McGRATH®MAC blade 1 than a Macintosh blade 1.

CLINICAL TRIAL REGISTRATION

jRCT1032220366.

Tracheal tube cuff pressure during anesthesia for robotic-assisted laparoscopic prostatectomy and the efficacy of an automatic cuff pressure controller (SmartCuff): observational studies of 1-sample paired data

PURPOSE

The cuff pressure of a tracheal tube may increase during robot-assisted laparoscopic surgery for prostatectomy (RALP), which requires pneumoperitoneum in a steep head-down position, but there have been no studies which confirmed this.

METHODS

In study 1, we studied how frequently the cuff pressure significantly increased during anesthesia for the RALP. In study 2, we studied if the SmartCuff (Smiths Medical Japan, Tokyo) automatic cuff pressure controller would minimize the changes in the intracuff pressure. With approval of the study by the research ethics committee (approved number: 20115), we measured the cuff pressures in anesthetized patients undergoing RALP and in those undergoing gynecological laparotomy (as a reference cohort), with and without the use of the SmartCuff.

RESULTS

In 21 patients undergoing RALP, a clinically meaningful increase (5 cmH₂O or greater) was observed in all the 21 patients (P = 0.00; 95% CI for difference: 86-100%), whereas in 23 patients undergoing gynecological laparotomy, a clinically meaningful decrease (5 cmH₂O or greater) was observed in 21 of 23 patients (91%, P < 0.0001; 95% CI for difference: 72-99%). With the use of the SmartCuff, there was no significant increase in the incidence of a clinically meaningful change in the intracuff pressure in either cohort.

CONCLUSION

The cuff pressure of a tracheal tube would frequently increase markedly in patients undergoing RALP, whereas it would frequently decrease markedly in patients undergoing gynecological laparotomy. The SmartCuff may inhibit the changes in the cuff pressure during anesthesia.

Videolaryngoscopy as a first-intention technique for tracheal intubation in unselected surgical patients: a before and after observational study

BACKGROUND

Using a Macintosh-style videolaryngoscope as a first-intention device for tracheal intubation of unselected patients in the operating room has not often been studied. We hypothesised that using a Macintosh-style videolaryngoscope as a first-intention device is associated with an increased proportion of easy tracheal intubation.

METHODS

In a quality improvement project for airway management aimed at implementing a Macintosh-style videolaryngoscope as a first-intention device, we included all consecutive tracheal intubations in adults from March, 2017 to September, 2020 in two French teaching hospitals. We divided the cohort into three temporal cohorts: the pre-intervention, implementation, and post-intervention periods. The primary outcome was the proportion of easy airway management. The secondary outcomes were the rescue technique, Cormack-Lehane III or IV view, and operator-reported difficulty of intubation. Data from one hospital compliant with the quality improvement project were compared with data from a non-compliant hospital.

RESULTS

A total of 26 692 tracheal intubations were performed. Among 11 938 intubations included in the compliant hospital, 5487 were included in the pre-intervention, 1845 in the implementation, and 4606 in the post-intervention periods. In comparison to the pre-intervention period, the proportions of easy tracheal intubation increased from 94.3% (5177 of 5487) to 98.7% (4547 of 4606)) in the post-intervention period (+4.4% [95% confidence interval 3.7-5.1%], P<0.001). In comparison to the pre-intervention period, all secondary outcome proportions were significantly lower in the post-intervention period. No significant changes were noted in the non-compliant hospital between the pre- and post-intervention periods.

CONCLUSIONS

Using a Macintosh-style videolaryngoscope as a first-intention device for tracheal intubation in the operating room was associated with a significant increase in the proportion of easy tracheal intubation, compared with use of the standard Macintosh laryngoscope.

[Tracheal rupture following endotracheal intubation for an emergency cesarean]

This is a case report of a 45-year-old patient, 39 weeks of gestation, who was intubated via rapid sequence induction (RSI) for an emergency cesarean. The indication for emergency cesarean was a pathological cardiotocography during the ejection phase following labor induction.Despite the primary use of a video laryngoscope, there was difficulty aligning the laryngeal axis. Therefore, an internal stylet was used to heavily angulate the endotracheal tube (ETT) to a hockey stick shape to enter the larynx.Postoperative dyspnea and extensive facial swelling were initially diagnosed as an allergic reaction. Only 22 h later the diagnosis of tracheal rupture was confirmed following computer tomography.We hypothesized that the mechanism of injury was due to excessive pressure transmitted to the tip of the ETT. This probably occurred due to a leverage effect caused by the withdrawal of the heavily bent stylet from the ETT, forcing an intratracheal cranial movement of the ETT.By conducting an experiment on a pig's trachea, we were able to visualize this mechanism of injury. In addition, we were able to demonstrate that bending the stylet to a similar angle as the laryngoscope blade led to minimal movement of the tip of the ETT.Therefore, when using a stylet during intubation, we recommend bending the ETT and stylet to the shape of the used laryngoscope blade and retracting the stylet at a similar angle to avoid complications, such as tracheal rupture.